Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds significant value beyond the annotations. It discloses the auth requirement (write-scope), ordering behavior (append at end), and the option to reorder via a sibling tool. Annotations only provide boolean hints (readOnlyHint=false, destructiveHint=false), so the description carries the full burden of behavioral disclosure and does so clearly.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences, front-loaded with the primary action, and each sentence adds crucial information (purpose, ordering, auth requirement). There is no wasted text; it is a model of conciseness.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers purpose, ordering, and auth. It does not describe the return value (no output schema) or the structure of the layout object, but the latter is partially handled by the schema and the sibling tool sonar_screenshot_layout_guide. For a simple append operation, the description is mostly complete, though a note about the layout guide would improve it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description does not add meaning beyond the schema: it mentions 'append a screen' but doesn't elaborate on the structure of the 'layout' object or the format of 'set_id'. The parameter information in the description is essentially redundant with the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses the specific verb 'append' and resource 'screen to a screenshot set', clearly distinguishing it from sibling tools like sonar_update_screenshot (update) or sonar_delete_screenshot (delete). The additional note about ordering ('at the end') and a sibling for reordering further clarifies the tool's unique role.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly states a prerequisite ('Requires a write-scope API key') and gives an alternative for reordering ('reorder with sonar_update_screenshot_set'). It implies the tool is for adding new screens rather than modifying existing ones, though it does not exhaustively list when not to use it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.